1. Field of the Invention
The invention relates to a DC-DC converter; in particular, to a power converter having an improved transient response and an operating method thereof
2. Description of the Prior Art
In recent years, power supply circuits have been widely used in different electronic products, such as portable electronic products, or computer products. The power supply circuit can provide voltage or current conversion or provide power of fixed voltage or current for the electronic products to operate. In the power supply circuits, a power integrated circuit is one of the necessary active components.
U.S. Pat. No. 6,696,825 discloses a DC-DC converter having a feature of forming an adjustable voltage range between a first voltage higher than the output voltage and a second voltage lower than the output voltage and detecting instant changes of the output voltage by a comparator circuit to generate corresponding change of pulse modulation width to drive the transistor to change the output current and the output voltage. Please refer to FIG. 1. FIG. 1 shows the circuit structure of the DC-DC converter.
As shown in FIG. 1, in order to have the function of generating real-time dynamic reaction to outer voltage changes, the DC-DC converter 20 in U.S. Pat. No. 6,696,825 needs an additional pin P to direct the output voltage Vout into the IC 55, and uses a specific detection circuit in the IC 55 to detect and analyze the output voltage Vout, then the DC-DC converter 20 determines the change of the pulse modulation width and takes appropriate response measure to achieve the aim of real-time dynamic reaction. However, the area and cost of the IC will be increased due to the disposing of additional pin P and specific detection circuit.
Therefore, the invention provides a power converter and an operating method thereof to solve the above-mentioned problems occurred in the prior arts.